Obese people have higher risks for diabetes, heart disease, arthritis—and injuries in car accidents? Yes, in part because they’re far less likely to wear a seat belt. That’s the finding of a study out of the University of Buffalo that will be presented at an upcoming meeting of the Society for Academic Emergency Medicine in Chicago.

The researchers analyzed data in the national Fatality Analysis Reporting System of the National Highway Traffic Safety Administration. The study included a third-of-a-million drivers involved in fatal crashes. Two years ago, the research group found that morbidly obese people were 56 percent more likely to die in a car crash than normal-weight car occupants. The new study revealed that drivers of normal weight are 67 percent more likely to wear a seat belt than are obese drivers—which could account for at least part of the increased death risk.

The researchers hypothesize that overweight people find belts uncomfortable and difficult to buckle. A weight-loss program can address the problem in the long run. An inexpensive seat belt extension can solve it today.